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611.
本研究项目设计了小型立式环型风洞系统和流场模拟两套实验装置。用工程流体力学实验的方法,对系统内气体压力、流量变化的调节控制方法、通风机的能量消耗,以及在检测平台系统工作段形成均匀流动流场的设计方法等工程实际问题,进行了一系列的试验研究。在试验研究的基础上确定了检测平台系统的设计方案。 相似文献
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Raghu Naath Singg Billy R. Webb 《Journal of the American Water Resources Association》1979,15(1):136-143
ABSTRACT: The major objective is to report the way the Delphi methodology was employed in an environmental study aimed at identifying and ranking goals and social impacts of Cooper Dam and Reservoir Project located in the East Texas area. The Delphi procedures were modified to accommodate the nature of social field under study. Data were collected through personal interviews from twenty-seven respondents representing the government agency responsible for planning the Project and three communities geographically contiguous to the project. The respondents were provided an initial list of the Project's goals and social impacts and were asked to rank them in terms of degree of importance and to add to the list other goals and impacts that they would consider necessary. Respondents were interviewed in two successive rounds. Data show that on the whole the Delphi procedures were helpful in action analysis of the Project by identifying and ranking its goals and social impacts in terms of selected criteria. 相似文献
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Ian D. Leith Lucy J. Sheppard David Fowler J. Neil Cape Matt Jones Alan Crossley Ken J. Hargreaves Y. Sim Tang Mark Theobald Mark R. Sutton 《Water, Air, & Soil Pollution: Focus》2004,4(6):207-218
Providing an accurate estimate of the dry component of N deposition to low N background, semi-natural habitats, such as bogs and upland moors dominated by Calluna vulgaris is difficult, but essential to relate nitrogen deposition to effects in these communities. To quantify the effects of NH3 inputs to moorland vegetation growing on a bog at a field scale, a field release NH3 fumigation system was established at Whim Moss (Scottish Borders) in 2002. Gaseous NH3 from a line source was released along of a 60 m transect, when meteorological conditions (wind speed >2.5 m s–1 and wind direction in the sector 180–215°) were met, thereby providing a profile of decreasing NH3 concentration with distance from the source. In a complementary study, using a NH3 flux chamber system, the relationships between NH3 concentrations and cuticular resistances were quantified for a range of NH3 concentrations and micrometeorological conditions for moorland vegetation. Cuticular resistances increased with NH3 concentration from 11 s m–1 at 3.0 g m–3 to 30 s m–1 at 30 g m–3. The NH3 concentration data and the concentration-dependent canopy resistance are used to calculate NH3 deposition taking into account leaf surface wetness. The implications of using an NH3 concentration-dependent cuticular resistance and the importance for refining critical loads are discussed. 相似文献
614.
玉米抗低温助长剂田间试验研究 总被引:13,自引:5,他引:8
为防御东北玉米低温冷害,研制了一种新型的玉米抗低温助长剂,其抗低温效果已为人工温控试验所证实。本项研究采用分期播种、地理播种和田间多处理对比试验方法,检验该化学制剂在影响玉米发育、生物量及产量性状方面的实用效果,并探求其适宜的浓度配比和喷施期次。研究结果表明,该制剂具有促生长、促早熟和使作物高产的性能,可防御延迟型冷害。施用时以1:400倍液和在营养生长期内两次喷施为佳。 相似文献
615.
田间增强UV-B辐射对麦田生态系统Fe营养和累积的影响 总被引:4,自引:0,他引:4
研究大田栽培和自然光条件下,模拟UV-B辐射(UV-B,280nm ~315nm )增强对麦田生态系统Fe营养和累积的影响.在4 个生育期中,UV-B辐射显著增加叶和穗Fe含量,显著降低根Fe 含量,并改变茎Fe 含量.叶Fe累积对UV-B辐射的响应有明显的生育期之间的差异. 分蘖期无显著变化,拔节期和扬花期显著增加,而成熟期显著降低.在各生育期,UV-B辐射显著降低叶、根和穗Fe累积.UV-B辐射显著降低春小麦不同生育期Fe总累积,在5.31kJ·m-2 UV-B辐射下,降低最显著.UV-B辐射还降低春小麦群体Fe输出.麦田土壤速效Fe含量增加是春小麦群体Fe输出降低的结果,可能导致土壤库中Fe 储量的增加. 相似文献
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